1. Field of the Invention
The present invention relates to a manufacturing method for a semiconductor device having a high-frequency type semiconductor chip encapsulated in a hollow type hermetically sealed package.
2. Description of the Related Art
In some conventional semiconductor devices, a hollow type package is provided to encapsulate a semiconductor chip, which is designed to handle high frequencies in a package. This hollow type package reduces the interconnect capacitance of the device, since the dielectric constant in air is lower than that resulting in resin-sealed chips. Hence, this hollow type package design can improve the high-frequency characteristics of the device.
FIGS. 7A and 7B show an examplary construction of a conventional high-frequency semiconductor device, as described in Japanese laid-open patent publication No. 10-173117. This device includes a base substrate 1 formed of ceramic or the like; leads 2 for connecting external devices; a cap 3 also composed of ceramic or the like; a chip mounting section 4 disposed between the leads 2; a semiconductor chip 5 mounted on the surface of the mounting section 4; and bonding wires 6 connecting the semiconductor chip 5 to each of the leads 2. The semiconductor chip 5 is hermetically sealed within a package 7 formed by the cap 3.
When manufacturing this type of device, the leads 2 are supplied in the form of a lead frame. The semiconductor chip 5 is die-bonded and wire-bonded to the lead frame. Next, the base substrate 1 is affixed to the bottom surface of the lead frame. The cap 3 is affixed to the top of the base substrate 1 with the lead frame interposed therebetween. Finally, the lead frame is trimmed and reformed.
However, the shortcoming of this package design is that the leads 2 protrude from the base substrate 1. Accordingly, a large amount of area is required when mounting this package on a printed circuit board. Another problem of this manufacturing method is that the base substrate 1 and cap 3 must be fixed to the lead frame for each chip. Consequently, the manufacturing process is complex and not suitable for mass production.
In view of the foregoing, it is an object of the present invention to provide a manufacturing method suitable for the mass production of semiconductor devices each having a high-frequency type semiconductor chip encapsulated in a hermetically sealed hollow type package. It is another object of the present invention to provide a method of manufacturing the same type of semiconductor devices that do not require a large amount of area for mounting on a printed circuit board.
These objects and others will be attained by a manufacturing method for a semiconductor device, comprising: preparing a common substrate having opposing first and second main surfaces and a plurality of mounting sections formed at the first main surface, each of the mounting sections being provided with an island section for mounting a semiconductor chip and electrode sections disposed on opposing sides of the island section for connecting to the electrodes of the semiconductor chip; fixing a semiconductor chip onto each of the mounting sections; fixing a cover over the plurality of mounting sections for hermetically sealing each of the semiconductor chips, which is mounted in a hollow space formed thereby; and separating the mounting sections, each retaining their corresponding portions of cover and substrate to produce a semiconductor device having a hermetically sealed semiconductor chip.